1. Field of the Invention
The present invention generally relates to a fuel pump control apparatus for an engine. More specifically, the present invention relates to an engine fuel pump control apparatus that controls a main fuel pump and a subordinate fuel pump.
2. Background Information
A conventional fuel pump control apparatus has a main fuel pump arranged in a main fuel tank and a subordinate fuel pump arranged in a subordinate fuel tank for supplying fuel to an engine (e.g., Japanese Laid-Open Patent Publication No. 2003-293877). This conventional fuel pump control apparatus normally uses fuel from the main fuel tank. A driver operated switch is provided such that the driver can operate the subordinate fuel pump to use fuel from the subordinate fuel tank when the amount of fuel remaining in the main fuel tank becomes low.
Since only the fuel in the main fuel tank is used to run the engine under normal circumstances, the subordinate fuel pump goes for long periods of time without being used and could possibly become seized. Therefore, the existing fuel pump control apparatus attempts to solve the problem of the subordinate fuel pump becoming seized. Specifically, the conventional fuel pump control apparatus drives the subordinate fuel pump in coordination with a signal issued from an ignition switch when the engine is started. In this way, the fuel pump provided in the subordinate fuel tank is periodically operated to prevent it from becoming seized.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved air-fuel ratio control apparatus. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.